“He was a great teacher. He always tried to explain things if you didn’t understand,” said former student Corey Kroll. “He’s like a nerdy math guy. He’s awesome. He’s not somebody that would do this.”

“She’s 17. She’s old enough to make her own decisions. He shouldn’t get trouble for this, what he did,” said student Christian Rizo.

“It’s kind of wrong I would say,” another student said.

Authorities were tipped off to the alleged affair by another teacher at the school, who notified the superintendent, who called the cops.

The former student told authorities the two had sex when she was a junior and senior at the school.

Many students who spoke with CBS 2 were supportive, but parents were not.

“Too much of this stuff going on. Parents got to watch their own kids. That’s what they got to do,” said parent Cliff Rinbrand.

Prosecutors say while the age of consent in New Jersey is 16, cases like this become criminal when they involve a teacher and a student. There is no statute of limitation when it comes to filing sexual assault charges in the state.

“These teachers and other types of professionals who are in supervisory positions over our kids, they do these things and no matter when they do them, sooner of later they will get caught,” said John Molinelli, Bergen County Prosecutor.

Prosecutors say the female student, who is not being identified, is cooperating but is upset. If found guilty, Greco could face up to 30 years behind bars.

The superintendent of schools says the district does not comment on personnel matters but that he applauds the teacher who came forward and reported the rumors.

Greco has been suspended. He faces sexual assault and endangering charges, and is being held on $100,000 bail.